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QSAR ANALYSIS OF SORPTION-CORRECTED RATE CONSTANTS FOR REDUCTIVE BIOTRANSFORMATION OF HALOGENATED AROMATICS
Citation:
TebesStevens, C L. AND W J. Jones. QSAR ANALYSIS OF SORPTION-CORRECTED RATE CONSTANTS FOR REDUCTIVE BIOTRANSFORMATION OF HALOGENATED AROMATICS. Presented at 220th American Chemical Society National Meeting, Washington, DC, August 20-24, 2000.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
The inherent coupling among geochemical and microbial reactions may have significant effects on the environmental fate of a containinant. For example, sorption processes may decrease the concentration of an organic compound in solution, thereby reducing the biodegradation rate of the compound. In order to conduct meaningful comparisons of biodegradation rates in systems with different organic carbon concentrations or sediment-to-solution ratios, the observed biotransforrnation rate constants must be corrected to obtain a more "intrinsic" rate constant for an equivalent sediment-free system. In this study, a set of literature rate constants for reductive dehalogenation of halogenated aromatics were corrected for hydrophobic partitioning. The sorbed fractions of the target compounds were assumed to be unavailable for biodegradation, and the sorption process was assumed to be at equilibrium. Multivariate statistical analyses demonstrated that the correlation of the sorption-corrected rate constants to physicochemical and molecular descriptors of the compounds was stronger than that of the observed rate constants.